Mineral material, such as rock, can be extracted from the ground for crushing by means of either explosions or excavation. The rock may also be natural stone and gravel, or construction waste. Both mobile crushers and stationary crushing applications are used for crushing. The material to be crushed is fed with an excavator or wheel loader to a feed hopper of a crusher or crushing plant, from where the material to be crushed may fall into the throat of the crusher, or a feeder transfers the rock material towards the crusher. The mineral material to be crushed may also be recyclable material, such as concrete, bricks, or asphalt.
Jaw crushers are suitable for, for example, rough crushing at quarries or crushing of construction material. According to the operating principle of the jaw crusher, crushing takes place against jaws, termed fixed and moving jaw.
A known jaw crusher comprises a pitman which is supported at an upper end by side plates of the jaw crusher's frame through an eccentric. A rear part of the jaw crusher's frame is fastened between the side plates. Below the eccentric, the pitman is supported by the rear part of the frame through a toggle plate. A tie rod is arranged between a lower part of the pitman and the rear part of the frame; the tie rod is spring-loaded and pulls the pitman backwards towards the toggle plate.
JP2003053204 presents a jaw crusher where a toggle plate is supported at its ends by bearings having two grooves for the toggle plate. The end of the toggle plate may be changed into the second groove in the bearing. In addition, the bearing may be turned, in which case the grooves will settle at different positions with regard to the crusher's frame or pitman. To change the angle of the toggle plate, at least the toggle plate must be detached from the crusher. To detach the toggle plate, sufficient space, time, and a number of people must be reserved. When detaching, one person holds the pitman up with a load belt, another holds the toggle plate up, and the third switches the place of the bearing, for example.
The object of the invention is to avoid or mitigate problems related to prior art and/or to provide new technical alternatives. One object of the invention is to improve the adjustability of the jaw crusher. One object of the invention is to improve occupational safety. One object of the invention is to improve the effectiveness of the jaw crusher.